A new and distinct Malus tree named ‘Summer Wonder’ as herein described and illustrated being a genetic variation from an open pollinated seedling of the crabapple, Malus baccata×Malus pumila ‘Antonovka’, was discovered in the nursery production seedling row by the sole inventor, Mr. Kenneth Gill in Baileyton, Ala. on Jun. 5, 1998. This cultivar is of Russian origin and is used in the nursery industry as a hardy root stock for Malus cultivars. Seeds from this open pollinated cultivar were sown and cultivated in the field for use as budding root stock. The ‘Antonovka’ seed came from Quincy, Wash., 98848 collected from green leaf forms of ‘Antonovka’. The new Malus cultivar named ‘Summer Wonder’ by the discoverer, Mr. Gill, has been observed and evaluated for six years as a landscape plant and has maintained its unique purple leaf characteristics. It has not been sold, shared or released and has not been made public in any publications. Summer Wonder crabapple has been successfully asexually propagated by budding in September and October on Malus domestica and ‘Antonovka’ open pollinated seedling rootstock in Cullman, Ala. at the inventor's nursery. Budding success rate has been consistent at about 80-90% success rate. The clonal progeny of the parent plant are identical to the parent and offer the same distinct characteristics. The clonal progeny of the parent plant are true to type, identical to the parent and offer the same distinct characteristics.